Learning about Data Structures (Stacks) using Hacker Rank exercise - Balanced Brackets

balancedbrackets.js

// Cleaner implementation without Stacks, but using its concept

function main(arr) {
    var solution = [],
        balanced = true;
    for (var i = 0; i < arr.length; i++){
        switch(arr[i]){
          case '{':
          case '(':
          case '[':
            solution.push(arr[i]);
            break;
          default:
            if(solution.length === 0 || !checkBalanced(solution.pop(), arr[i])){
             balanced = false;
            }
            break;
        }
    }
    if(balanced && solution.length === 0){
      return 'YES';
    } else {
      return 'NO';
    }
}

function checkBalanced(first, second){
  var pair = [
    ['[', ']'],
    ['{', '}'],
    ['(', ')']
  ];
  for(var i = 0; i < pair.length; i++){
    if(pair[i][0] === first && pair[i][1] === second){
      return true;
    }
  }
  return false;
}

console.log(main('[{[{})[][[}{}]]]}]}]'));
console.log(main('[][](){{[{()}]}}{}([])'));